inoperable power and operation issue

First,have you tried a known good charger? If not,you need to.

It could be anything really. Did you drop it at all? Anything that would indicate physical damage?

It could also be a bad battery…maybe. Sony is a good brand,and their batteries are higher quality controlled. But it’s still possible that it went bad. But many devices would work plugged in without the battery.

One suspect is the charger port. If this wore down and got loose,it may not make good electrical contact. Unless it’s obviously broken,you’d have to take it apart to make sure it’s not broken. Basically,you need to take it apart.

It could be the power button. Does it click normally?

If not any of these issues,it is likely the circuit board itself has a bad component(maybe power management chip or a short).

If you’re lucky,it’s something simple. But even the simple micro USB port would require soldering to replace.

Good luck. Let me know if you need more help.